PolyFeed/PolyFeed/ParserProviders/HtmlParserProvider.cs

120 lines
3.5 KiB
C#

using System;
using System.IO;
using System.Net;
using System.Threading.Tasks;
using System.Xml;
using Fizzler.Systems.HtmlAgilityPack;
using HtmlAgilityPack;
using Microsoft.SyndicationFeed;
using Microsoft.SyndicationFeed.Atom;
using PolyFeed.Helpers;
namespace PolyFeed.ParserProviders
{
public class HtmlParserProvider : IParserProvider
{
private XmlWriter xml = null;
private AtomFeedWriter feed = null;
public string Identifier => "html";
public HtmlParserProvider()
{
}
public void SetOutputFeed(AtomFeedWriter inFeed, XmlWriter inXml) {
xml = inXml;
feed = inFeed;
}
public async Task ParseWebResponse(FeedSource source, WebResponse response)
{
await Console.Error.WriteLineAsync("[Builder/Html] Parsing Html");
// Parse the HTML
HtmlDocument html = new HtmlDocument();
using (StreamReader reader = new StreamReader(response.GetResponseStream()))
html.LoadHtml(await reader.ReadToEndAsync());
HtmlNode document = html.DocumentNode;
document.AbsolutifyUris(new Uri(source.Feed.Url));
await Console.Error.WriteLineAsync("[Builder/Html] Generating feed content");
// Add the title
await feed.WriteTitle(ReferenceSubstitutor.Replace(source.Feed.Title, document));
await feed.WriteSubtitle(ReferenceSubstitutor.Replace(source.Feed.Subtitle, document));
// Add the logo
if (source.Feed.Logo != null) {
HtmlNode logoNode = document.QuerySelector(source.Feed.Logo.Selector);
xml.WriteElementString("logo", logoNode.Attributes[source.Feed.Logo.Attribute].Value);
}
// Add the feed entries
foreach (HtmlNode nextNode in document.QuerySelectorAll(source.Entries.Selector))
{
await addEntry(source, nextNode);
}
}
private async Task addEntry(FeedSource source, HtmlNode nextNode)
{
HtmlNode urlNode = nextNode.QuerySelector(source.Entries.Url.Selector);
if (urlNode == null)
throw new ApplicationException("Error: Failed to match entry url selector against an element.");
string url = source.Entries.Url.Attribute == string.Empty ?
urlNode.InnerText : urlNode.Attributes[source.Entries.Url.Attribute].DeEntitizeValue;
Uri entryUri = new Uri(new Uri(source.Feed.Url), new Uri(url));
AtomEntry nextItem = new AtomEntry() {
Id = entryUri.ToString(),
Title = ReferenceSubstitutor.Replace(source.Entries.Title, nextNode),
Description = ReferenceSubstitutor.Replace(source.Entries.Content, nextNode),
ContentType = "html"
};
nextItem.AddLink(new SyndicationLink(entryUri, AtomLinkTypes.Alternate));
if (source.Entries.Published != null) {
nextItem.Published = DateTime.Parse(
nextNode.QuerySelectorAttributeOrText(
source.Entries.Published
)
);
}
if (source.Entries.LastUpdated != null) {
nextItem.LastUpdated = DateTime.Parse(
nextNode.QuerySelectorAttributeOrText(
source.Entries.LastUpdated
)
);
}
else if (source.Entries.Published != null) // Use the publish date if available
nextItem.LastUpdated = nextItem.Published;
else // It requires one, apparently
nextItem.LastUpdated = DateTimeOffset.Now;
if (source.Entries.AuthorName != null) {
SyndicationPerson author = new SyndicationPerson(
nextNode.QuerySelectorAttributeOrText(source.Entries.AuthorName).Trim(),
""
);
if (source.Entries.AuthorUrl != null)
author.Uri = nextNode.QuerySelectorAttributeOrText(source.Entries.AuthorUrl);
nextItem.AddContributor(author);
}
else
nextItem.AddContributor(new SyndicationPerson("Unknown", ""));
await feed.Write(nextItem);
}
}
}